Toggle switch mechansim



Aug 27, 1968 E. G. HADERER 3,399,285

TOG'GLE SWITCH MECHAN I SM Filed Dec. SO, 1966 7 Sheets-Sheet l FIG.|.

l5 Ih-r-i Allg- 27, 1968 E. G. HADERER 3,399,285

TOGGLE SWITCH MECHANSM Filed Dec. 50, 1966 7 Sheets-Sheet Z TOGGLE SWITCH MECHANISM 7 Sheets-Sheet .filed Dec.

Aug. 27, 1968 E. G. HADERER 3,399,285

TOGGLE SWITCH MECHANISM Filed Deo. 30, 1966 7 Sheets-Sheet 4 Aug. 27, 1968 E. G. HADERER 3,399,285

TOGGLE SWITCH MECHANSM Filed Dec. CSO, 1966 '7 Sheets-Sheet 5 Aug. 27, 196s E. G. HADERER 3,399,285

TOGGLE SWITCH MECHANISM Filed Dec. 30, 1966 7 Sheets-Sheet 6 Aug- 27, 1968 E. G. HADERER 3,399,285

TOGGLE SWITCH MECHANISM Filed Dec. 30, 1966 '7 Sheets-Sheet 'l' 3,399,285 TOGGLE SWITCH MECHANISM Edward G. Haderer, Plainville, Mass., assignor to Texas Instruments Incorporated, Dallas, Tex., a corporation of Delaware Filed Dec. 30, 1966, Ser. No. 606,336 13 Claims. (Cl. 200-67) ABSTRACT F THE DISCLOSURE A toggle-type switch mechanism for actuating and deactuating switches wherein movements of a pivoted toggle arm force a roller over inclined surfaces pivotally mounted and underslung on the arm pivot, the roller shifting the positions of the surfaces for switch operation. In some embodiments, the roller is spring biased to enable it to be retracted and extended as it moves over the surfaces. In another embodiment the surfaces are resiliently mounted so that the surfaces deect under pressure of the roller. In two embodiments the surfaces actuate a switch in either of two positions of movement. In another embodiment the mechanism can be positioned in a neutral position or in either of two moved positions.

Background of the invention The invention relates to mechanisms of the toggle type for actuating and deactuating switches. Known toggle mechanisms for actuating switches may operate in such a way that there is a continuously decreasing pressure on the switch actuator -as the switch is being deactuated, resulting in what is known as a teasing operation, which is undesirable. In the copending application Ser. No. 606,080, tiled Dec. 30, 1966, by Carlton E. Sanford for a Nontease Switch, a nontease switch is disclosed and claimed. The present -application discloses improved arrangements of parts for constructing such switches.

Summary of the invention Among the several objects of this invention may be noted the provision of mechanisms for positively actuating or deactuating a switch substantially instantaneously; the provision of a snap-acting toggle mechanism for operating a switch wherein the toggle must move past a specific position to actuate or deactuate a switch, and movement of the toggle toward said position will not actuate or deactuate the switch; the provision of an improved toggle mechanism for a plurality of switches which will not operate by teasing; the provision of a toggle mechanism for a plurality of switches some of which are actuated or deactuated when the toggle is in each of two positions and the toggle being positionable in a third position where all of the switches are in their normally open or normally closed positions; and the provision of a toggle mechanism for a switch which permits constant application of force to a switch to actuate the switch and instantaneous removal of the force to deactuate the switch. Other objects and features will be in part apparent and in part pointed out hereinafter.

Switch mechanisms of the inveniton comprise a housing adapted to receive a switch which is to be actuated and deactuated by the mechanism. A toggle arm is pivotally mounted relative to the housing. Switch actuating means are underslung for pivotal movement on the toggle pivot States Patent O 3,399,285 Patented Aug. 27, 1968 Fice between first and second positions for actuating and deactuating the switch. The switch actuating means comprises a irst of a pair of surfaces said first surface being inclined relative to a second surface and the surfaces meeting at a point of resistance such as a rise oir peak. A roller is moved between the iirst and second surfaces over the peak by pivoting the arm. Biasing means holds the roller in contact with the surfaces and exerts a force on Vthe switch actuating means tending to hold it in one of its positions until the roller passes over the peak, and thereafter it tends to bias the actuating means into the other position and hold it in the other position. In one form of the invention there are several such underslung paired surfaces for obtaining three, rather than two switch operating positions of the toggle arm.

Brief description of the drawings FIG. 1 is an elevation, partially broken away, showing a toggle mechanism of the invention as it is used in a switch assembly for actuating land deactuating a plurality of switches;

FIG. 2 is a fragmentary section taken along line 2-2 of FIG. l;

FIG. 3 is a View similar to FIG. 1 showing a modification;

FIG. 4 is an enlarged fragmentary section taken along line 4 4 of FIG. 3;

FIG. 5 is a fragmentary section taken along line 5 5 of FIG. 4;

FIG. 6 is a view similar to FIGS. 1 and 3 showing another embodiment of the invention;

FIG. 7 is a view like FIG. 6 but showing a moved position; and

FIG. 8. is a fragmentary section taken lalong line 8-8 of FIG. 7.

Corresponding reference characters indicate corresponding parts through the several views of the drawings.

Description of the preferred embodiments Referring to FIGS. l and 2, a cup-shaped housing or support generally designated 1 comprises a top 3 having four integral walls 5, 7, 9 and 11. All of 4the walls are substantially of the same size and shape so that the housing is sq-uare in transverse cross section. A plate 13 mounted in the housing is supported by the walls 5, 7, 9 and 11. A plurality of conventional electrical switches 15 are threaded in and carried by plate 13. Each is of the so-called microswitch type having an initial open or closed position to which it returns. Each switch 15 has three terminals 17 at the lower end of the switch for connecting the switches in electrical circuits. A switch actuator 19 at the upper end of each switch is adapted to be depressed for actuating the switch. When pressure is released from the actuator the switch is deactuated. Actuation of the switch may either close a normally open switch or open a normally closed switch. For the particular shape and size of switch housing shown in the drawings, four switches 15 can be accommodated and mounted in pairs at each side of the housing. When the mechanism is being assembled the switches are adjusted relative to plate 13 so that the two switches along the side 5 of the housing are simultaneously actuated and deactuated and similarly the switches along the side 9 of the housing are simultaneously actuated or deactuated. The switches at the left side of the housing are always actuated when the switches at the other side of the housing are deactuated. When the switches are properly adjusted potting 20 is provided in the lower part of the housing around the switches to hold the switches in their adjusted positions.

The top 3 of the housing has a hole 21 through its center. A cylindrical bushing 23 positioned above the base f the housing is generally concentric with the center of opening 21. A ange 25 projects radially outwardly from the bushing and is secured to the top 3 of the housing, thereby mounting the bushin-g on the housing. Secured to the bushing is a threaded nipple 27 which provides means for securing the housing to a support or other member. Bushing 23 and nipple 27 may be formed as an integral element if so desired.

An elongate cylindrical sleeve 29 is movable about a pivot pin 31 which extends through bushing 23 and the nipple 27. The lower end portion of sleeve 29 projects into the housing through hole 21. A rocking arm 33, secured to the upper end of sleeve 29, provides means for swinging the sleeve about pivot 31. Sleeve 29 and arm 33 together comprise an actuating arm for operating the mechanism.

A plunger 35 has a cylindrical end portion 37 positioned within the sleeve 29. The central part of the plunger is closed by a wall designated 39. A spring 41 reacts from pivot pin 31 against wall 39 to bias the plunger out of the lower end of the sleeve. The lower end of the plunger has two spaced legs 43 which receive the ends of a pin or axle 45, the latter mounting a roller 47.

A yoke generally designated 49 comprises a pair of spaced and generally parallel arms 51 joined at their lower end by a cross piece 53. Pivot 31 extends through the upper end portion of each arm 51 thereby pivotally to mount the yoke on the pivot. Sleeve 29 and roller 47 are between the arms as shown in FIG. 2.

A U-shape slider 55 in housing 1 has a bight portion 56 adjacent top 3 and side portions 58, 60 which are adjacent the walls 7 and 9. Struck out from the slider 55 is an arm portion 57 which extends into the center portion of the housing and between arms 51. A spring 59 extends from wall 9 of the housing toward the arm 57 for biasing the slider 55 toward .the left as viewed in FIG. 1. A large hole 62 in the center of bight 56 permits limited movement of the slider 55 to the left and right as viewed in FIG. 1. Since arms 51 straddle plunger 35 and sleeve 29, movement of the sleeve and plunger to the right as viewed in FIG. 1 will be opposed by spring 59 to return the sleeve and plunger to the left. A spring retainer on wall 9 of the housing and the arm 57 hold the spring in place in the housing.

As arm 33 is swung from its FIG. l position to move roller 47 to the right, the sleeve 29 engages arm 57 of the side and must compress spring 59 to move the roller to the position where the switches shown at the right in FIG. 1 will be actuated as explained more fully below. Roller 47 will remain in this moved position only until the arm 33 is released at which time spring 59 acting through the slide biases the sleeve 29 back to the FIG. 1 position. In other words, the switch mechanism will not remain in its moved position although it can be moved to said position against the force of spring 59. This type of operation is desirable whenever the switches 15 adjacent wall 9 are to be only momentarily actuated, such as might occur for actuating a fuse in an emergency situation. Slider 55 and spring 59 are optional and when they are not provided the roller 47 will remain in either of its two moved positions.

The yoke assembly 49 further comprises a substantially at switch actuator plate 63 positioned beneath the crosspiece.53 and a ramp member 65, the latter having end portions 67 tixed to the upper surface of the plate and intermediate web portions 69 and 71 which slope upward from plate 63 and meet at a peak or ridge or rise 73 at the center of the yoke assembly immediately above crosspiece 53. The webs 69 and 71 of the member 65 have inclined upper surfaces which constitute ramps. Roller 47 rides along these surfaces. The webs are somewhat narrower than the plate 63, as shown in FIG. 2, and they are located between the arms 51. Webs 69 and 71 are secured to the crosspiece 53 so that movement of the plate 63 and the ramp member 65 causes the entire underslung assembly to pivot about the axis of the pivot 31.

In operation, roller 47 rolls along the surface of web 69, over ridge 73 and onto the surface of web 71, and in the reverse direction back onto web 69. Spring 41 in sleeve 29 biases the roller 47 toward the end portions 47 of the ramp member. By forcing arm 33 from an inclined position through a vertical position into the opposite inclined position, thereby to move roller 47 along surfaces 69 and 71, the plunger is retracted into sleeve 29 against spring 41 until the roller reaches and crosses ridge 73. Then the spring 41 forces the plunger back out of the sleeve 29 as the roller slides down the opposite inclined surface. As this movement occurs the yoke assembly 49 is immediately swung about pivot 31 from the position shown in FIG. l wherein plate 63 contacts housing wall 9 and the switch actuators 19 of the switches 15 near Wall 5. This actuates these switches to a position wherein plate 63 contacts the wall 5 and the switch actuators 19 of the switches near wall 9, thereby deactuating the switches near wall 5 and actuating the switches near wall 9. AS the roller moves up the inclined surfaces of webs 69 and 71, plate 63 remains in rm contact with the actuators of the actuated switches due to the gradually increasing compression of spring 41 and the lateral component of the spring force which acts on the surfaces of web 69, 71 to hold the entire yoke assembly in place. This avoids intermittent on-off operation (called teasing) frequently resulting from unstable toggle mechanisms. Thus the toggle mechanism of the invention can be referred to as a nontease switch. When actuation and deactuation occurs, it is positive and is substantially instantaneous. Spring 41 holds the parts in the FIG. 1 position or in the moved position (wherein roller 47 is on surface 71) unless slide 55 and spring 59 are provided, in which case the roller is forced back over peak 73 onto surface 69 as soon as the arrn 33 is released.

Another embodiment of the invention is illustrated in i FIGS. 3-5 of the drawings. The assembly of this embodiment also provides the desirable positive and instantaneous actuation and deactuation of switches obtained -by the assembly of FIGS. l and 2. This embodiment comprises a switch housing 81 having a rectangular top 83 and four sides 85, 87, 89 and 91. The top has a hole 93 through it. A cylindrical bushing mounted on the top is in axial alignment with the center of hole 93. A threaded nipple 97 surrounds bushing 95 and provides means for attaching the switch to another article. A sleeve 99 is pivoted 0n bushing 95 and nipple 97 by a pin 101. The lower end portion of the sleeve is slotted as shown in 103 to provide two legs 105. A roller 107 between legs 105 rotates about a pin 109 extending through the roller and into the legs 105. Thus roll 107 is not free to move vertically relative to pin 101. However, sleeve 99 and roller 107 are movable about the axis of pin 101 by throwing an arm 110 which is secured to sleeve 99 similar to the manner shown in FIG. l. Arm 110 and sleeve 99 comprise the operating or toggle arm of this assembly.

A switch actuator assembly generally designated 111 comprises a pair of spaced legs 113 which project through hole 93 of the housing into bushing 95. Pivot 101 passes through the legs 113 thereby to pivotally mount them in the housing. At the bottom of each leg 113 there is a foot 115 which projects outwardly away from the other leg. Feet 115 are substantially perpendicular to the legs 113. Each leg 113 has an elongate generally vertically extending slot 117 through it. A switch actuator plate 121. is secured to the bottom of feet 115 by rivets 123. The actuator plate has four laterally extending fingers 125 at each side of the feet 115. The fingers are inclined upwardly somewhat as shown in FIGS. 3 and 4.

A pair of posts 127 are mounted on the ends of the actuator plate and the feet 115 by rivets 129 which project up through the feet and plate into the bottom of the post. Each post has a head 131 at the top thereof which forms a stop to limit upward movement of a guide plate generally designated 133. End portions 135 of the guide plate have holes therethrough which receive the posts 127 so that the plate may slide on the post. Springs 137 surrounding posts 127 react from feet 115 against the lower surface of the ends of the guide plate to bias the plate upwardly into engagement with the heads 131 when the actuator plate 121 is at either of its two normal positions. However, this mounting permits movement of the guide downwardly against the biasing force of springs 137 when the toggle mechanism is moved from one position to another.

The guide 133 has a central portion 139 which is substantially perpendicular to the end portions 135. The central portion 139 projects through slots 117 in legs 113. Thus the guide plate is movable vertically relative to legs 113 but movable with the legs when they are swung in an arc about pivot 101.

The upper portion of the central part 139 of the guide is cut away between the legs along a line 141 (FIG. 4) so that only the lower portion 143 of the center part of the guide extends between the legs. Two anges 145 (FIG. 3) project in opposite directions from the center part 143'of the guide and are secured to the lower surfaces of the track member 147. The track member has two inclined surfaces 149 and 151 which meet at a peak 153. Roller 107 rolls along the surfaces 149 and 151.

In operation, assuming that the parts are in the position shown in FIG. 3, tongue 110 is swung to the left to cause the roller 107 to move along surface 149 toward peak 153. As this occurs the roller pushes downwardly on the track member 147 to force it against the guide 133 which in turn moves downwardly through slots 117 in legs 113. This movement is opposed by the biasing force of spring 137 and, until the roller 107 reaches peak 153, the switch actuator 121 remains in the FIG. 3 position. However, when the roller passes over peak 153 and begins rolling down surface 151, the biasing force of spring 137 causes the entire assembly 111 quickly to swing to the left about the axis of pivot 101, thereby moving the switch actuator 121 from its FIG. 3 position wherein it engages wall 89 into a second position wherein it engages wall 85. As this occurs the switches adjacent the left wall 85 in the housing are deactuated and those positioned along the right wall 89 are actuated. Also, as this movement occurs the track member 147 is returned to its upper position by the biasing force of spring 137. Thus it will be seen that the operation of the switch mechanism of FIGS. 3-5 is similar to that shown in FIGS. 1 and 2, the embodiments differing principally in that in the FIGS. 1 and 2 embodiment the roller is moved vertically within sleeve 29 whereas the FIGS. 3-5 embodiment has a roller which is fixed relative to the supporting sleeve and the surface along which its rolls move toward or away from the roll. In other respects the switch mechanism of FIGS. 3-5 is quite similar to that shown in FIGS. 1 and 2.

FIGS. 6-8 show another embodiment which is similar to the embodiment of FIGS. 1 and 2, except for the actuating mechanism, and therefore corresponding reference characters have been used to designate the same or similar parts. In this case a twin switch actuating mechanism is generally designated 161. This comprises first an arm 163 which is pivoted about pin 31. At the lower end of the arm there is an integral generally horizontally extending plate 165. Plate 165 supports a second plate 167, the latter comprising an end portion 169 which is secured to plate 165 and two portions 171 and 173 (FIG. 6) which are inclined relative to each other and which meet at a peak 175. Roller 47 is adapted to roll along surface 171 and 173 when the switch actuating mechanism is moved between the position shown in FIG. 6 and FIGS. 7 and 8 wherein two of the switches are actuated. Secured to the bottom of plate is a switch actuating member 177 which extends substantially entirely across the housing between walls 7 and 11 as shown in FIG. 8.

There is a second switch actuating mechanism designated 161a which is identical to the mechanism 161 except that its mounting on pivot 31 is displaced 180 so that the arm 163a is on the opposite side of sleeve 29 from the arm 163. Accordingly the numerals 161a-177a have been used to designate the parts of the mechanism 161a which correspond to like parts of the mechanism 161.

Operation of the embodiment of FIGS. 6-8 i-s as follows:

When the switch is in the neutral position shown in FIG. 6, roller 47 is between and bears against both inclined surfaces 173 and 173a of the switch actuating mechanisms and the downward component of the biasing force of spring 41 has a lateral component acting against the inclined surfaces which tends to move the switch actuating mechanism 161 toward the left and mechanism 161a toward the right. This separates the inner edges of plates 165, 165a and holds the outer edges of the plate against the housing walls 5 and 9. Under this condition plates 177 and 177a are spaced from all switch actuators 19.

When the arm 33 is swung clockwise from the FIG. 6 to the FIG. 7 position, roller 47 moves upwardly along the inclined surface 173 until it rides over peak 175. Spring `41 permits this upward movement of the roller. During this movement of the roller the actuating member 177 remains in the position shown in FIG. 6, but as soon as the roller passes over the peak 175 and starts down surface 171 the lateral component of the biasing force of spring 41 acts against surface 171, thereby forcing the switch actuating member 161 to pivot about the axis of pin 31 until plate 165 engages plates 165a as shown in FIG. 7. This pivotal movement brings the switch actuating member 177 into engagement with the switch actuator of the switches 15 adjacent wall 5 of the housing, thereby actuating these switches. The switch actuator mechanism 16141 remains in the neutral position due to engagement of plate 165a and wall 7. By swinging the arm 33 in the opposite counterclockwise direction the roller 47 can be moved onto surface 171a, at which time the switches 15 adjacent wall 9 will be actuated by the member 17711. Thus the switch of FIGS. 6-8 can be placed in a neutral position (FIG. 6) or actuated positions, where it actuates one or the other switch at one side or the other of the housing while the switch at the other side of the housing remains deactuated.

It is to be understood that in all forms of the invention the point of resistance to movement of the driving means for the underslung switch operator, such as the roller, instead of taking the form of a rise or peak may take other forms vsuch as a depression or the like. It will also be understood that, by pivoting said underslung switch operator on the same ypivot p-oint as that of the toggle arm, the number of parts required is minimized and the overall size 0f the switch considerably reduced. By threading the switches to be operated into the housing support for the toggle parts, calibration for proper switch operation may be conveniently performed at the time of assembly, these switches being locked into calibrated positions by suitable means such as the insertion of the potting compound referred to above.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings, shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A toggle switch mechanism comprising at least one switch, a support for mounting the switch, a toggle arm pivoted with respect to the support about an axis, switch ractuating means pivoted with respect to the support about the same axis as the toggle arm for movement between first and second positions for actuating and deactuating the switch, said switch actuating means comprising a plate having a irst surface inclined relative to a second surface, said surfaces meeting at a rise, drive means movable on and between the first and second surfaces across said rise, said drive means being connected with said toggle arm and movable along one of the surfaces to the other surface by pivoting the toggle arm, and means for resiliently biasing together the drive means and said surfaces, thereby to exert a force on the switch actuating means tending to hold it in one of its pivoted positions until the drive means passes across said rise and thereafter tending 'to bias the actuating means into the other of its pivoted positions and hold it in said other position.

2. A toggle switch mechanism comprising -at least one switch, a support for mounting the switch, a toggle arm pivoted with respect to the support about an axis, switch -actuating means mounted for pivotal movement with respect to the support between first and second positions for actuating and deactuating the switch, said switch actuating means comprising a plate engageable with the switch to actuate and deactuate the switch, a iirst surface inclined yrelative to a second surface, said surfaces meeting at a rise and being movable together toward and away from said plate, drive means movable on and between the lirst and second surfaces across said rise, said drive means being connected with said toggle arm and movable along one of the surfaces to the other surface by pivoting the arm, said surfaces being between the plate and the drive means, and means for resiliently biasing the surfaces away from the plate and .toward the drive means, thereby to exert a force on the switch `actuating means tending to hold it in one of its pivoted positions until the drive means passes across said rise and hereafter tending to bias the actuating means into the other of its pivoted positions and hold it in said other position.

3. Mechanism according to claim 2 wherein the switch actuating means further comprises an arm attached to the plate and pivoted for movement about the same axis as the toggle arm.

4. Mechanism according to claim 2 wherein said drive means is a roller mounted on an end of the toggle arm, and the distance between the roller and the axis about which the toggle arm moves is the same for all positions of the toggle arm.

S. A switch mechanism comprising at least a pair of switches, a support for mounting the switches, a toggle arm pivoted with respect to the support, switch actuating means mounted for pivotal movement with respect to the support beween first and second positions for actuating one switch and deactuating the other switch in each of its positions, said actuating means comprising a pivotally mounted 'arm supporting a plate engageable with the switches for actuating and deactuating them, said means further comprising a member having a iirst surface inclined relative to a second surface, said surfaces meeting at a rise and being jointly movable toward and away from said plate, means biasing the surfaces away from said plate, and a drive member carried by said arm and engageable with said surfaces during movement of said toggle arm for moving said surfaces toward said plate against the baising force of said biasing means.

6. A switch mechanism according to claim 5 wherein .the drive member comprises a roller engageable with said surfaces, the axis of the roller being the same distance from the pivotal axis of the toggle arm throughout movement of the roller along said surfaces and across said rise.

7. A switch mechanism according to claim 6 wherein the switch actuating arm is pivoted about the same axis as the toggle arm, said switch actuating arm having an elongate slot therein, said actuating means further comprising a plate slidable in said slot and biased toward said inclined surfaces by said biasing means, and said biasing means comprising a spring reacting from said actuator plate against said last-named plate for exerting a force between said surfaces and said roller.

8. A switch mechanism according to claim 5 for operating plural pairs of switches, wherein said plate engages said switches for actuating and deactuating one switch in each pair each time the plate is pivoted, said plate having a pair of spaced posts extending upwardly therefrom through holes in said member, said inclined surfaces being between said posts, and said biasing means comprising a compression spring coiled about each of said posts for biasing said member away from said plate.

9. A switch mechanism comprising at least two switches, a support having two stops, a toggle arm pivoted 'with respect to the support, two switch actuating means for actuating and deactuating the switches, each of said means being mounted for separate swinging movement with respect to the support between switch actuating and deactuating positions, each of said means when in the deactuating position contacting one of said stops and when in the actuating position contacting the other actuating means, each of said means having rst and second surfaces inclined upwardly and meeting at a rise, drive means having a connection with said arm and being movable by pivoting said arm along said surfaces of both actuating means, means for resiliently biasing the drive means toward said surfaces, the drive means -when in one position between the two actuating means being in engagement with a surface of each actuating means thereby forcing the actuating means away from each other into deactuating positions and into contact with the stops, and the drive means when in either of two other positions being engageable with the other surface of one or the other actuating means, thereby exerting a force on it to swing it to actuating position and against the unengaged actuating means to hold the latter in the deactuating position against one of the stops.

10. A switch mechanism according to claim 9 wherein the drive means comprises a roller carried by a plunger, the plunger reciprocating in a sleeve movable by the toggle arm, and the biasing means comprises a spring in the sleeve reacting against the plunger to bias the plunger outwardly with respect to the sleeve and thereby bias the roller into engagement with said surfaces.

11. A switch mechanism according to claim 10 wherein both of the switch actuating means are mounted for movement about the same pivotal axis as the toggle arm.

12. A switch mechanism comprising at least one switch, a housing for containing the mechanism and the switch, a toggle arm having an operating end outside of the housing and an end in the housing carrying a roller, switch actuating means, means for pivoting the toggle arm and the switch actuating means at one center on the housing, said switch actuating means being movable with respect to the housing between first and second positions for actuating and deactuating the switch, said switch actuating means having a first surface and a second surface, said surfaces having a connection of a shape resisting without preventing movement of the roller from one surface to the other, said roller being movable along one of the surfaces, across said connection, and to the other surface by pivoting the toggle arm, and means for resiliently biasing together the roller and said surfaces, thereby to exert a force on the switch actuating means tending to hold it in one of its pivoted positions until the drive means passes across said connection and thereafter tending to bias the actuating means into the other of its pivoted positions and hold it in said other position.

' 9 10 13. A switch mechanism according to claim 12, where- FOREIGN PATENTS in the switch for calibration is threaded into the housing, 791 307 2/1958 Great Britain whereby its position is adjusted relative to the switch 9621745 1/1964 Great Britain actuafmg meafls- 1,198,286 6/1959 France.

5 1,389,212 4/1965 France.

References Cited OTHER REFERENCES UNITED STATES PATENTS 2,248,362 7/1941 Krieger. 212671203 12/1941 Kflegef- 10 ROBERT K. SCHAEFER, Primary Examiner.

2,311,465 2/1943 Parker. 3,115,555 12/1963 Lescarbura, D. SMITH, IR., Assistant Examiner.

German printed application 1,165,713, March 1964. 

